Optical information recording medium and optical information recording and reproducing apparatus

Inactive Publication Date: 2004-05-13
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0033] Thus, the invention described herein makes possible the advantage of providing an optical information recording medium and an optical information recording and reproducing apparatus in which reading errors may be reduced both on the lands and the grooves of the guide grooves.

Problems solved by technology

Therefore, even if a signal recording may be satisfactorily performed on either one of a land track and a groove track during a step of demodulating a reproduced signal, a great deal of error is generated on the other kind of track in some cases.
Accordingly, in a conventional recording medium for performing a land / groove recording, there exists problems to be solved in that the configuration of a recording thin film is required to be optimized and that the guide grooves on the substrate must be shaped with high precision.
In such a case, the medium may be used exclusively for reproducing the information, and the recording of the information thereon is impossible.
For example, the shapes of the guide grooves may become ununiform; the distribution of the intensity of the light beam emitted from the recording and reproducing apparatus may be distorted; or the sensitivity of the photodetector and the like may become inconstant.

Method used

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  • Optical information recording medium and optical information recording and reproducing apparatus
  • Optical information recording medium and optical information recording and reproducing apparatus
  • Optical information recording medium and optical information recording and reproducing apparatus

Examples

Experimental program
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example 2

[0075] In this example, a method for enabling the focusing to be optimized for both a land and a groove and optimal tracking of the guide grooves by switching the servo conditions for a land and a groove when a light beam is irradiated on an optical information recording medium.

[0076] As focusing techniques for focusing a light beam on an optical information recording medium, a knife edge method, an astigmatism method and the like are known. According to the knife edge method, the detection system to be used becomes disadvantageously large because the optical members are required to be positioned with high precision. On the other hand, according to the astigmatism method, it is easy to downsize a detection system. According to the astigmatism method, however, in performing a precise focusing control for both of a land and a groove, which is the main objective of the present invention, a difference is not supposed to be generated between a land and a groove in an ideal state. But, in...

example 3

[0088] In this example, a method for switching demodulation conditions for a land and a groove when an information signal is demodulated based on the reflected light from the light beam irradiated on the optical information recording medium by omitting or simplifying a step in which the recording conditions are switched for a land and a groove during recording. The objective of the method of this example is to correct the difference in the signal amplitude and the difference in the mark length dependence of the signal amplitude among various differences between the reproduced signal of a land and that of a groove. It is noted that the mark length difference refers to an amplitude dependence between a shortest recorded mark and a longest recorded mark among the recorded marks to be formed in response to the information signal.

[0089] FIG. 12 shows the detail of the binary coding portion 20. A high-pass filter (HPF) 120 outputs high-frequency components of the output signal 14s from th...

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Abstract

An optical information recording and reproducing apparatus for recording and reproducing an information signal on / from both concave portions and convex portions of guide grooves formed on a recording medium is disclosed. The optical information recording and reproducing apparatus includes: an optical portion for focusing a light beam emitted from a light source on the recording medium; a focusing control portion for controlling a focal point of the light beam; a tracking control portion for controlling the position of the light beam; a selection portion for selecting which of the concave portions and the convex portions of the guide grooves are used for recording or reproducing; a polarity inverting portion for inverting the polarity of an output signal from the tracking control portion depending on a result selected by the selection portion; a waveform setting portion for setting a modulation pattern for the light; and a signal reproduction portion for demodulating the information signal from a light reflected or transmitted by recorded marks recorded on the recording medium; wherein at least one of the focusing control portion, the tracking control portion, the waveform setting portion and the signal reproduction portion has at least two kinds of operation conditions for recording and reproducing the information signal on / from the concave portions and the convex portions of the guide grooves, and wherein the operation conditions are selected depending on the result selected by the selection portion.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to an optical information recording medium and an optical information recording and reproducing apparatus for recording and reproducing information by using a light beam. More particularly, the present invention relates to an optical information recording medium and an optical information recording and reproducing apparatus allowing for obtaining a higher track density by recording a signal on both lands and grooves of the guide grooves thereof.[0003] 2. Description of the Related Art[0004] Optical disks, optical cards, optical tapes and the like are well-known as recording mediums (or recording members) for recording and / or reproducing information by the use of an optical means. In order to record information on such a recording medium, a laser beam is generally used as a light source. More specifically, information is recorded by precisely focusing a light beam through a lens so as to irradiate the light beam on ...

Claims

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Application Information

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IPC IPC(8): G11B7/0045G11B7/005G11B7/007G11B7/085G11B7/09G11B7/125G11B11/105
CPCG11B7/0045G11B7/00456G11B7/005G11B7/007G11B7/00718G11B7/00736G11B11/10595G11B7/08511G11B7/0901G11B7/0908G11B7/094G11B7/126G11B7/1267G11B7/08505
InventorNISHIUCHI, KENICHIMIYAGAWA, NAOYASUOHNO, EIJIAKAHIRA, NOBUO
OwnerPANASONIC CORP